Revision 32db864d33c21fd70a217ba53cb7224889354ffb authored by Nikolay Aleksandrov on 30 August 2017, 09:48:59 UTC, committed by David S. Miller on 30 August 2017, 22:26:11 UTC
If sch_hhf fails in its ->init() function (either due to wrong user-space arguments as below or memory alloc failure of hh_flows) it will do a null pointer deref of q->hh_flows in its ->destroy() function. To reproduce the crash: $ tc qdisc add dev eth0 root hhf quantum 2000000 non_hh_weight 10000000 Crash log: [ 690.654882] BUG: unable to handle kernel NULL pointer dereference at (null) [ 690.655565] IP: hhf_destroy+0x48/0xbc [ 690.655944] PGD 37345067 [ 690.655948] P4D 37345067 [ 690.656252] PUD 58402067 [ 690.656554] PMD 0 [ 690.656857] [ 690.657362] Oops: 0000 [#1] SMP [ 690.657696] Modules linked in: [ 690.658032] CPU: 3 PID: 920 Comm: tc Not tainted 4.13.0-rc6+ #57 [ 690.658525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 690.659255] task: ffff880058578000 task.stack: ffff88005acbc000 [ 690.659747] RIP: 0010:hhf_destroy+0x48/0xbc [ 690.660146] RSP: 0018:ffff88005acbf9e0 EFLAGS: 00010246 [ 690.660601] RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000 [ 690.661155] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff821f63f0 [ 690.661710] RBP: ffff88005acbfa08 R08: ffffffff81b10a90 R09: 0000000000000000 [ 690.662267] R10: 00000000f42b7019 R11: ffff880058578000 R12: 00000000ffffffea [ 690.662820] R13: ffff8800372f6400 R14: 0000000000000000 R15: 0000000000000000 [ 690.663769] FS: 00007f8ae5e8b740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000 [ 690.667069] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 690.667965] CR2: 0000000000000000 CR3: 0000000058523000 CR4: 00000000000406e0 [ 690.668918] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 690.669945] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 690.671003] Call Trace: [ 690.671743] qdisc_create+0x377/0x3fd [ 690.672534] tc_modify_qdisc+0x4d2/0x4fd [ 690.673324] rtnetlink_rcv_msg+0x188/0x197 [ 690.674204] ? rcu_read_unlock+0x3e/0x5f [ 690.675091] ? rtnl_newlink+0x729/0x729 [ 690.675877] netlink_rcv_skb+0x6c/0xce [ 690.676648] rtnetlink_rcv+0x23/0x2a [ 690.677405] netlink_unicast+0x103/0x181 [ 690.678179] netlink_sendmsg+0x326/0x337 [ 690.678958] sock_sendmsg_nosec+0x14/0x3f [ 690.679743] sock_sendmsg+0x29/0x2e [ 690.680506] ___sys_sendmsg+0x209/0x28b [ 690.681283] ? __handle_mm_fault+0xc7d/0xdb1 [ 690.681915] ? check_chain_key+0xb0/0xfd [ 690.682449] __sys_sendmsg+0x45/0x63 [ 690.682954] ? __sys_sendmsg+0x45/0x63 [ 690.683471] SyS_sendmsg+0x19/0x1b [ 690.683974] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 690.684516] RIP: 0033:0x7f8ae529d690 [ 690.685016] RSP: 002b:00007fff26d2d6b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 690.685931] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f8ae529d690 [ 690.686573] RDX: 0000000000000000 RSI: 00007fff26d2d700 RDI: 0000000000000003 [ 690.687047] RBP: ffff88005acbff98 R08: 0000000000000001 R09: 0000000000000000 [ 690.687519] R10: 00007fff26d2d480 R11: 0000000000000246 R12: 0000000000000002 [ 690.687996] R13: 0000000001258070 R14: 0000000000000001 R15: 0000000000000000 [ 690.688475] ? trace_hardirqs_off_caller+0xa7/0xcf [ 690.688887] Code: 00 00 e8 2a 02 ae ff 49 8b bc 1d 60 02 00 00 48 83 c3 08 e8 19 02 ae ff 48 83 fb 20 75 dc 45 31 f6 4d 89 f7 4d 03 bd 20 02 00 00 <49> 8b 07 49 39 c7 75 24 49 83 c6 10 49 81 fe 00 40 00 00 75 e1 [ 690.690200] RIP: hhf_destroy+0x48/0xbc RSP: ffff88005acbf9e0 [ 690.690636] CR2: 0000000000000000 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent e89d469
blk-mq-tag.c
/*
* Tag allocation using scalable bitmaps. Uses active queue tracking to support
* fairer distribution of tags between multiple submitters when a shared tag map
* is used.
*
* Copyright (C) 2013-2014 Jens Axboe
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/blk-mq.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-tag.h"
bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
{
if (!tags)
return true;
return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
}
/*
* If a previously inactive queue goes active, bump the active user count.
*/
bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
{
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
!test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
atomic_inc(&hctx->tags->active_queues);
return true;
}
/*
* Wakeup all potentially sleeping on tags
*/
void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
{
sbitmap_queue_wake_all(&tags->bitmap_tags);
if (include_reserve)
sbitmap_queue_wake_all(&tags->breserved_tags);
}
/*
* If a previously busy queue goes inactive, potential waiters could now
* be allowed to queue. Wake them up and check.
*/
void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
{
struct blk_mq_tags *tags = hctx->tags;
if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return;
atomic_dec(&tags->active_queues);
blk_mq_tag_wakeup_all(tags, false);
}
/*
* For shared tag users, we track the number of currently active users
* and attempt to provide a fair share of the tag depth for each of them.
*/
static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
struct sbitmap_queue *bt)
{
unsigned int depth, users;
if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
return true;
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return true;
/*
* Don't try dividing an ant
*/
if (bt->sb.depth == 1)
return true;
users = atomic_read(&hctx->tags->active_queues);
if (!users)
return true;
/*
* Allow at least some tags
*/
depth = max((bt->sb.depth + users - 1) / users, 4U);
return atomic_read(&hctx->nr_active) < depth;
}
static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
struct sbitmap_queue *bt)
{
if (!(data->flags & BLK_MQ_REQ_INTERNAL) &&
!hctx_may_queue(data->hctx, bt))
return -1;
if (data->shallow_depth)
return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
else
return __sbitmap_queue_get(bt);
}
unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
{
struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
struct sbitmap_queue *bt;
struct sbq_wait_state *ws;
DEFINE_WAIT(wait);
unsigned int tag_offset;
bool drop_ctx;
int tag;
if (data->flags & BLK_MQ_REQ_RESERVED) {
if (unlikely(!tags->nr_reserved_tags)) {
WARN_ON_ONCE(1);
return BLK_MQ_TAG_FAIL;
}
bt = &tags->breserved_tags;
tag_offset = 0;
} else {
bt = &tags->bitmap_tags;
tag_offset = tags->nr_reserved_tags;
}
tag = __blk_mq_get_tag(data, bt);
if (tag != -1)
goto found_tag;
if (data->flags & BLK_MQ_REQ_NOWAIT)
return BLK_MQ_TAG_FAIL;
ws = bt_wait_ptr(bt, data->hctx);
drop_ctx = data->ctx == NULL;
do {
prepare_to_wait(&ws->wait, &wait, TASK_UNINTERRUPTIBLE);
tag = __blk_mq_get_tag(data, bt);
if (tag != -1)
break;
/*
* We're out of tags on this hardware queue, kick any
* pending IO submits before going to sleep waiting for
* some to complete.
*/
blk_mq_run_hw_queue(data->hctx, false);
/*
* Retry tag allocation after running the hardware queue,
* as running the queue may also have found completions.
*/
tag = __blk_mq_get_tag(data, bt);
if (tag != -1)
break;
if (data->ctx)
blk_mq_put_ctx(data->ctx);
io_schedule();
data->ctx = blk_mq_get_ctx(data->q);
data->hctx = blk_mq_map_queue(data->q, data->ctx->cpu);
tags = blk_mq_tags_from_data(data);
if (data->flags & BLK_MQ_REQ_RESERVED)
bt = &tags->breserved_tags;
else
bt = &tags->bitmap_tags;
finish_wait(&ws->wait, &wait);
ws = bt_wait_ptr(bt, data->hctx);
} while (1);
if (drop_ctx && data->ctx)
blk_mq_put_ctx(data->ctx);
finish_wait(&ws->wait, &wait);
found_tag:
return tag + tag_offset;
}
void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
struct blk_mq_ctx *ctx, unsigned int tag)
{
if (!blk_mq_tag_is_reserved(tags, tag)) {
const int real_tag = tag - tags->nr_reserved_tags;
BUG_ON(real_tag >= tags->nr_tags);
sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
} else {
BUG_ON(tag >= tags->nr_reserved_tags);
sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
}
}
struct bt_iter_data {
struct blk_mq_hw_ctx *hctx;
busy_iter_fn *fn;
void *data;
bool reserved;
};
static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
{
struct bt_iter_data *iter_data = data;
struct blk_mq_hw_ctx *hctx = iter_data->hctx;
struct blk_mq_tags *tags = hctx->tags;
bool reserved = iter_data->reserved;
struct request *rq;
if (!reserved)
bitnr += tags->nr_reserved_tags;
rq = tags->rqs[bitnr];
if (rq->q == hctx->queue)
iter_data->fn(hctx, rq, iter_data->data, reserved);
return true;
}
static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
busy_iter_fn *fn, void *data, bool reserved)
{
struct bt_iter_data iter_data = {
.hctx = hctx,
.fn = fn,
.data = data,
.reserved = reserved,
};
sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
}
struct bt_tags_iter_data {
struct blk_mq_tags *tags;
busy_tag_iter_fn *fn;
void *data;
bool reserved;
};
static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
{
struct bt_tags_iter_data *iter_data = data;
struct blk_mq_tags *tags = iter_data->tags;
bool reserved = iter_data->reserved;
struct request *rq;
if (!reserved)
bitnr += tags->nr_reserved_tags;
rq = tags->rqs[bitnr];
iter_data->fn(rq, iter_data->data, reserved);
return true;
}
static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
busy_tag_iter_fn *fn, void *data, bool reserved)
{
struct bt_tags_iter_data iter_data = {
.tags = tags,
.fn = fn,
.data = data,
.reserved = reserved,
};
if (tags->rqs)
sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
}
static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
busy_tag_iter_fn *fn, void *priv)
{
if (tags->nr_reserved_tags)
bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
}
void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
busy_tag_iter_fn *fn, void *priv)
{
int i;
for (i = 0; i < tagset->nr_hw_queues; i++) {
if (tagset->tags && tagset->tags[i])
blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv);
}
}
EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
{
int i, j, ret = 0;
if (!set->ops->reinit_request)
goto out;
for (i = 0; i < set->nr_hw_queues; i++) {
struct blk_mq_tags *tags = set->tags[i];
if (!tags)
continue;
for (j = 0; j < tags->nr_tags; j++) {
if (!tags->static_rqs[j])
continue;
ret = set->ops->reinit_request(set->driver_data,
tags->static_rqs[j]);
if (ret)
goto out;
}
}
out:
return ret;
}
EXPORT_SYMBOL_GPL(blk_mq_reinit_tagset);
void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
void *priv)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
struct blk_mq_tags *tags = hctx->tags;
/*
* If not software queues are currently mapped to this
* hardware queue, there's nothing to check
*/
if (!blk_mq_hw_queue_mapped(hctx))
continue;
if (tags->nr_reserved_tags)
bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
}
}
static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
bool round_robin, int node)
{
return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
node);
}
static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
int node, int alloc_policy)
{
unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node))
goto free_tags;
if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin,
node))
goto free_bitmap_tags;
return tags;
free_bitmap_tags:
sbitmap_queue_free(&tags->bitmap_tags);
free_tags:
kfree(tags);
return NULL;
}
struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
unsigned int reserved_tags,
int node, int alloc_policy)
{
struct blk_mq_tags *tags;
if (total_tags > BLK_MQ_TAG_MAX) {
pr_err("blk-mq: tag depth too large\n");
return NULL;
}
tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
if (!tags)
return NULL;
tags->nr_tags = total_tags;
tags->nr_reserved_tags = reserved_tags;
return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
}
void blk_mq_free_tags(struct blk_mq_tags *tags)
{
sbitmap_queue_free(&tags->bitmap_tags);
sbitmap_queue_free(&tags->breserved_tags);
kfree(tags);
}
int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
struct blk_mq_tags **tagsptr, unsigned int tdepth,
bool can_grow)
{
struct blk_mq_tags *tags = *tagsptr;
if (tdepth <= tags->nr_reserved_tags)
return -EINVAL;
tdepth -= tags->nr_reserved_tags;
/*
* If we are allowed to grow beyond the original size, allocate
* a new set of tags before freeing the old one.
*/
if (tdepth > tags->nr_tags) {
struct blk_mq_tag_set *set = hctx->queue->tag_set;
struct blk_mq_tags *new;
bool ret;
if (!can_grow)
return -EINVAL;
/*
* We need some sort of upper limit, set it high enough that
* no valid use cases should require more.
*/
if (tdepth > 16 * BLKDEV_MAX_RQ)
return -EINVAL;
new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, 0);
if (!new)
return -ENOMEM;
ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
if (ret) {
blk_mq_free_rq_map(new);
return -ENOMEM;
}
blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
blk_mq_free_rq_map(*tagsptr);
*tagsptr = new;
} else {
/*
* Don't need (or can't) update reserved tags here, they
* remain static and should never need resizing.
*/
sbitmap_queue_resize(&tags->bitmap_tags, tdepth);
}
return 0;
}
/**
* blk_mq_unique_tag() - return a tag that is unique queue-wide
* @rq: request for which to compute a unique tag
*
* The tag field in struct request is unique per hardware queue but not over
* all hardware queues. Hence this function that returns a tag with the
* hardware context index in the upper bits and the per hardware queue tag in
* the lower bits.
*
* Note: When called for a request that is queued on a non-multiqueue request
* queue, the hardware context index is set to zero.
*/
u32 blk_mq_unique_tag(struct request *rq)
{
struct request_queue *q = rq->q;
struct blk_mq_hw_ctx *hctx;
int hwq = 0;
if (q->mq_ops) {
hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu);
hwq = hctx->queue_num;
}
return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
(rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
}
EXPORT_SYMBOL(blk_mq_unique_tag);
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